Others need it, e.g. cpack and distsrc in the next commit.

Adding RPATH entries manually and via CMAKE_*RPATH* facilities may lead
to conflict of authorities. This instance in particular tries to add the
same RPATH entry twice (fails on MacOS).

GCC 7 and below don't know -Wclass-memaccess and emit
a warning about the unknown warning we are trying to
shut up. This suppresses that warning too.

GCC 7 complains that it doesn't know the warnings we are trying
to disable, so we just exchanged one kind of warning for another
before. This way is more convincing to GCC that we know what we
are doing.

Before reaching the changed line, c is set to be an index into buff,
so the strings can overlap if no copy is performed, and that leads
to unpredictable behaviour.

Fixes: ROOT-9601

include/llvm/ADT/SmallVector.h:296:13: warning:
‘void* memcpy(void*, const void*, size_t)’ writing to an object of type
‘struct std::pair<clang::CXXMethodDecl*, const clang::FunctionProtoType*>’
with no trivial copy-assignment; use copy-assignment or copy-initialization
instead [-Wclass-memaccess]

       memcpy(Dest, I, (E - I) * sizeof(T));
       ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Link to compilation error:
https://epsft-jenkins.cern.ch/view/ROOT%20Nightly/job/root-nightly-master/1977/LABEL=mac1012,SPEC=noimt/parsed_console/

The error is due to a bug in clang3.5, reproducible in isolation:
https://godbolt.org/z/jtYXv6

The workaround is to avoid specifying the template parameters of a
template base class -- the full type is injected in the derived class
anyway (thanks Axel!).

In case the array of sums of TH1 was created before
painting the stack (for instance by calling GetMaximum() on the stack),
the automatic colouring of the stack was not working.

tree/treeplayer/src/TTreeFormula.cxx:2550:23: warning: ‘char* strncat(char*, const char*, size_t)’ output may be truncated copying between 0 and 1023 bytes from a string of length 1023 [-Wstringop-truncation]
                strncat(second,work,kMaxLen-1-strlen(second));
                ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.../tree/tree/src/TTree.cxx: In member function ‘virtual TFile* TTree::ChangeFile(TFile*)’:
.../tree/tree/src/TTree.cxx:2642:33: warning: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size between 1 and 10 [-Wformat-truncation=]
             snprintf(fcount,10, %s%d, uscore, fFileNumber);
                                 ^~~~~~
.../tree/tree/src/TTree.cxx:2642:33: note: directive argument in the range [-2147483648, 1]
.../tree/tree/src/TTree.cxx:2642:21: note: ‘snprintf’ output between 2 and 21 bytes into a destination of size 10
             snprintf(fcount,10, %s%d, uscore, fFileNumber);
             ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.../tree/tree/src/TTree.cxx:2632:33: warning: ‘%d’ directive output may be truncated writing between 1 and 10 bytes into a region of size between 1 and 10 [-Wformat-truncation=]
             snprintf(fcount,10, %s%d, uscore, fFileNumber);
                                 ^~~~~~

In core/zip/inc/Compression.h was introduced RCompressionSetting class with set of enumerated classes for compression level, compression algorithm and default compression settings